Lithium is a long-standing psychiatric medicine of unclear mechanism. A number of enzymes have been proposed as potential targets of lithium action, including inositol monophosphatase, a family of structurally related phosphomonoesterases, and the protein kinase glycogen synthase kinase-3 (see [4] and the DrugBank link). Administered as salt formulations such as the carbonate PubChem CID 11125